mckenzie



No. 6l0,687. Patented Sept. I3, I898.

D. J. MCKENZIE.

GRATE.

(Application filed Ian. 5, 1898.) (No Model.) 3 Sh eetsSheet I.

Tu: NORRIS PETERS w. PHOTO-LITHOp WASNINGTON u. c.

No. 610,687. Patented Sept. 13, I898. D. J. McKENZlE.

5, I IMIMIIIY,

NITED PATENT rricn.

DOUGAL J. MCKENZIE, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE MCKENZIEFURNACE COMPANY, OF SAME PLACE.

GRATE.

SPECIFICATION forming part of Letters Patent No. 610,687, datedSeptember 1 3, 1898.

Application filed January 5, 1898. Serial No. 665,663. (No model.)

To all whom it may concern:

Be it known that I, DOUGAL J. MCKENZIE, a citizen of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in Grates, of which thefollowing is a specification.

The object of my invention is to provide a simple, economical, andefficient grate; and the invention consists in the features,combinations, and details of construction herein-.

after described and claimed.

In the accompanying drawings, Figure 1 is a vertical sectional elevationof a boiler and I 5 furnace fitted with a grate constructed inaccordance with my improvements; Fig. 2, an enlarged plan view of aportion of a grate constructed in accordance with my improvements. Figs.3 and 4. are sectional elevations 2o taken on lines 3 and 4,respectively, of Fig. 2; and Fig. 5, a transverse sectional elevationtaken on the line 5 of Fig. 2.

In the art to which this invention relates it is well known that in thegrates now in com- 2 5 mon use a certain amount of grate-surface isneeded to generate sufficient heat units to evaporate a given number ofpounds of water to get the required boiler-pressure. This is so wellknown that in planning furnaces a 0 certain amount of space is generallyinsisted upon in order to obtain the necessary heat units. It is alsowell known that-in the use of bituminous coal such coal will clinker andclog the ordinary grates now in use and that 3 5 in order to overcomethis various styles of grates have been invented, a great many of thetype known as shaking-grates and mechanical stokers.

My invention, therefore,'is intended, pri- 0 marily, to provide a grateof such construction that a less amount of grate-space is necessary togenerate the required heat units than has hitherto been required as thestandard.

A further object of my invention is to pro vide a grate of suchconstruction and arrangement that shaking is unnecessary and that willminimize the objections of run- 11in g of the coal and clogging of thegrate, all of which will be more fully hereinafter 5o explained.

In constructing a grate in accordance with my improvements I make agrate-bar A and provide it with an upper surface A, constructed oflongitudinal and transverse bars a and a, the transverse bars havingprojections, lugs, or teeth a opposite each other, so

as to form What might be termed double comb -shaped apertures a arrangedtransversely, so as to pass through the surface of the grate-bars. Theseteeth a are tapered 6o downwardly, as shown particularly in Fig.

5, so as to afford clearance for the ashes of the coal and allow thesame to readily pass through the openings.

In order to support the grate-surface in an efficient manner and providefor the admission of atmospheric air to the burning fuel, the grate-baris provided with a lower longitudinal sustaining portion A and eachtrans verse rib or bar a is supported by means of partitions or ribs Awhich are vertically and transversely disposed and extend from the upperto the sustaining portion and connect them in one integral bar. Thesepartitions or ribs are concaved at the sides, as shown particularly inFigs. 1, 3 and 4, so that they form what might be termed arched recesses13 between each grate-bar, into which air may pass and circulate in acylindrical manner to be detained and from which sufficient air canalways be drawn to the grate-surface to sup port combustion.

It will also be observed from the foregoing description of theconstruction and operation and from an inspection of the figures of thedrawings, particularly Figs. 4 and 5, that there is a space between theupper portion of the grate A, which forms the grate-surface, and thelongitudinal supporting-bar A which is arranged underneath thegrate-surface. This space between the grate-surface and thesupporting-bar serves to furnish a continuous connection between thespaces formed between the bars, so that portions of the air whichcirculates between the bars may pass 5 through these spaces, and thusfacilitate the feeding of air to the fuel-box or fire chamber. This is amaterial advantage in that the air is detained and broken up intocurrents,which facilitates the feeding of the furnace.

An inspection of Figs. 3 and 4 will show that the lower sustainingportions of the gratebars are tapered, as at A and adapted to fit intapered recesses c of the side bars 0 and center bars 0. In the ordinaryfurnaces, four by four, I prefer to make the grate-bars in two pieceslongitudinally, as shown in Fig. 5, and support them on the side andmiddle bars. The upper surfaces of these side and center bars aretapered, as at a, so that the ashes in falling down will not be retainedon the upper surfaces thereof.

Fig. 1 shows a complete furnace constructed in accordance withmyimprovement,in which there are six grate-bars, and this furnace is ofthe ordinary size, four by four, having sixteen square feet. I find,however, from experiments, that while this amount of gratesurface isnecessary under the 01d construction of boilers I can cut it down atleast one bar and save about three feet of grate-surface, which is oftenquite a consideration in crowded centers of commerce. It will thereforebe seen that a grate-bar constructed in accordance with my improvementis more economical to use in that it requires less space to generateheat units than in boilers constructed in the old forms.

In use and from actual experiments I have found that the coal burns onthe grate-bar in seemingly individual piecesthat is, the coal rests onthe teeth over the comb-shaped openings and is distilled rapidly by theheat of the furnace, so that the incoming air seems to engage or combinewith the distilled gases and burn in jet-like flames, the ash droppingthrough readilyand easily in small pieces and not tending to clinker orclog. From these experiments I find that the air comes in through theash-pit and is resisted by the sustaining portions of the grate-bars andcircles between the same and is held in a measure therein to be easilydrawn up through the openings in the grate-surface, the entire grateforming, as it were, a mesh to economically support the fuel and admitthe necessary atair-space between it and the grate-surface and two ormore ribs or partitions vertically and transversely disposed to connectthe surface portion with the sustaining portion in one integral portion,substantially as described.

2. In a grate-bar, the combination of a surface portion provided withtransverse ribs or bars, projecting teeth on each side of the transverseribs and arranged to form combshaped openings through the grate, asustaining portion arranged underneath the gratesurface so as to providean air-space between it and the grate-surface longitudinally disposed,and a plurality of ribs or partitions transversely and verticallydisposed to connect the surface and sustainingportions in one integral.portion, substantially as described.

3. In a grate, several grate-bars each having a surface portion providedwith a plurality of double comb-shaped openings extending therethrough,a lower wedge-shaped sustaining portion, arranged in line with andunderneath the grate-surface so as to provide an air-space between itand the grate-surface anda plurality of vertically and transverselydisposed ribs or partitions connecting the surface and sustainingportions in one integral piece, in combination with supporting rods orbars provided with tapered recesses to receive the sustaining portionsof the bars and hold them in fixed operative position, substantially asdescribed.

4. In a furnace-grate, the combination of several grate-bars formed ofupper surface portions having a plurality of double combshaped openingstransversely disposed and extending therethrough, lower wedge-shapedsustaining portions longitudinally disposed, and arranged underneath thegrate-surface so as to provide an air-space between it and thegrate-surface a plurality of webs or partitions connecting the surfaceand sustaining portions in integral portions and concaved at either sideso as to provide arched recesses between adjacent grate-bars into whichair may circulate and be distributed, and side bars for the furnaceprovided with wedgeshaped recesses or pockets in their upper portions toreceive the sustaining portions of the grate-bars and removably hold thegrate-bars in fixed operative position, substantially as described.

DOUGAL J. MCKENZIE. Witnesses:

THOMAS F. SHERIDAN, J. WHITTIER BUFFUM.

